We saw our first dust disk last night with the LBTI nulling interferometer! First, the night details:
We carried out further nulling engineering last night, along with some test science to determine the state of the system. We began the night by optimizing our group delay tracker (also called the contrast gradient approach). This has allowed us to stabilize the phase, but has higher RMS variation than we need to hit our specs. We tried adding an integral term to this, and saw no improvement. Based on simulatons from Amali and Bertrand, we also tried merging the group delay and phase delay, to fine tune the performance. Also no improvement there. Its good to have ruled these out as the cause of the large RMS, but was disappointing.
We made more progress on scripting last night. Denis now has an automated routine for setting the group delay setpoint and routine. Dual position nodding was also further refined.
We took test data on fainter stars last night (1.7 Jy) with good results. This will be important for carrying out observations on the full HOSTS sample.
Finally, we looked at a star with a bright dust disk to test our performance. Denis carried out on-the-fly data reduction which confirmed we were seeing the disk. It made for a good end of the night.
Denis shows off the disk detection.
Bill and Rafael run the AO systems.
Our first detection. (rough reduction only).